Valve mechanism silencing device



Jan. 24, 1956 l. H. ABERCROMBIE VALVE MECHANISM SILENCING DEVICE Filed Nov. 24, 1952 6 1 m. 5 Um il iiwliir u. a

INVENTOR IAN HAMILTON ABERCROMBIE PATENT ATTORNEYS VALVE MECHANISM SILENCING DEVICE Ian H. Abercrombie, Calgary, Alberta, Canada Application November 24, 1952, Serial No. 322,177 1 Claim. (Cl. 123-90) My invention relates to new and useful improvements in silencing devices for valve mechanisms and in particular for silencing devices adapted to be associated with the overhead valve mechanism of conventional internal combustion engines, an object of my invention being to provide a device of the character herewithin described wherein the backlash and clearance normally associated with valve mechanisms is concentrated at one point in said system, and means are provided to absorb and eliminate noise emanating from this point.

A further object of my invention is to provide a device of the character herewithin described which as well as eliminating the noise normally associated with overhead valve mechanism, also eliminates any echo which may occur.

Still another object of my invention is to provide a device of the character herewithin described in which all of the backlash and clearance in the overhead valve mechanism is concentrated in one point and this location is totally submerged in oil at all times.

A still further object of my invention is to provide a device of the character herewithin described which is simple to install in conventional engines with the minimum of alterations thereto.

Still another object of my invention is to provide a device of the character herewithin described which is simple in construction, economical in operation and otherwise well suited for the purpose for which it is designed.

With the foregoing objects in view, and such other objects and advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, my invention consists essentially in the arrangement and construction of parts all as hereinafter more particularly described, reference being had to the accompanying drawings in which Figure 1 is a transverse cross-section of a conventional engine showing the overhead valve mechanism of my device in situ.

Figure 2 is an enlarged fragmentary view of the portion of Figure 1 incorporating my device.

Figure 3 is an enlarged side elevation of my device per se.

Figure 4 is a vertical section of Figure 3.

In the drawings like characters of reference indicate corresponding parts in the different figures.

Despite present day design of the internal combustion engines, it is still essential to provide working clearance between the various components which go to make up the overhead valve mechanisms and this clearance, no matter how small it may be, always results in mechanical noise which is very often magnified by echo while the engine is running. My invention overcomes the disadvantages of overhead valve mechanism by concentrating all of the backlash and clearance at one location and submerging this location in oil at all times, thereby eliminating any noise or echo which may emanate therefrom.

Proceeding now to describe my invention in detail, it will be seen upon reference to the accompanying drawings that I have illustrated a conventional engine in Figure 1, the important parts of which is the valve 1, rocker arm 2, push rod 3, cam follower 4 and cam shaft 5. It is well known that with an action such as this and in view of the difference in co-eflicient of expansion of the various materials utilized in the construction of an engine, considerable clearance is required between the components in order to ensure that the valve seats properly when the cam shaft is revolving in the non-operative position. It will also be appreciated that due to the relatively high speed of modern internal combustion engines, this clearance is taken up very sharply and tends to produce a relatively loud tap just prior to the valve being actuated.

My device then consists essentially in what I define as a preloader collectively designated 6 situated between the lower end 7 of the push rod and the upper end 8 of the cam follower 4. This preloader, in this embodiment, consists of a hollow cylindrical body portion 9 having a concave-convex head 10 upon the upper end thereof. A horizontal flange 11 extends outwardly from the head 10 and the concave upper surface 12 of the head extends upwardly through this flange to form a cup adapted to receive the lower ball end 13 of the aforementioned push rod 3.

Means to maintain the preloader in contact with the ball 13 and the cam follower 4 in perpetual contact with the cam 5 are provided and take the form, in this embodiment, of a coil spring 14 reacting between the underside of the flange 11 and the upper end of the cam follower 8 and it should be appreciated that this spring is strong enough to prevent clearance from existing between the upper end of the valve and the rocker arm, and between the rocker arm and the upper end of the push rod so that all clearance in the system is concentrated between the lower side 15 of the preloader and the upper end 16 of the cam follower.

In order to deaden or eliminate the sound initiated when the cam follower strikes the underside of the preloader, I have submerged this region in oil by the provision of a stand pipe 16 extending between the crank case 17 and the push rod container 18. It will be understood that normally oil draining from the overhead valve mechanism feeds through apertures in the'crank case upper wall 19, but by the provision of the stand pipe 16, this is permitted to collect there and form an oil bath 20, thus completely submerging the preloader at all times and deadening any sounds which may emanate therefrom.

In conclusion, it will be seen that a relatively small breather hole 21 is provided at the base of the cup communicating with the interior of the cylindrical body portion 9 of the preloader so that there is no possibility of an air lock occurring.

Since various modifications can be made in my invention as hereinabove described, and many apparently widely different embodiments of same made within the spirit and scope of the claim without departing from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

What I claim as my invention is:

A preloader device for the silencing of the valve mechanism noise in overhead internal combustion engines adapted to be situated between the lower end of the as sociated push rod and the upper end of the associated cam follower, said preloader device consisting of a substantially cylindrical body portion, a concavo-convex head on said body portion, a horizontal flange extending outwardly from said head, the concave portion of said head constituting a cup for receiving the lower end of the associated push rod and a breather hole situated at the bottom of said cup and extending through said head to the interior of said body portion, said preloader device Patented Jan. 24, 1956 being submerged in an oil bath, the base of said body portion being spaced above the associated cam follower actuating said push rod, and spring means reacting between t-he underside of. said flange and said earn: follower, whereby said push rod is in contact with the base of said cup.

References Cited in the file of this patent UNITED STATES PATENTS 986,175 Jones Mar. 7, 1911 Senkgiel M Oct. 14, 1919 Fisher June 30, 1936 Ashton Ian. 5, 1937 FOREIGN PATENTS Great Britain 1921 

